sudden lost power and lean out at 5psi, fuel pump? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 07-18-2010, 01:45 AM   #1
Junior Member
Thread Starter
 
Join Date: Jan 2008
Location: monterey park,ca
Posts: 67
Total Cats: 0
Default sudden lost power and lean out at 5psi, fuel pump?

I just installed my 460cc injectors today and couple pulls. The car suddenly lean out to 17:1 when i have 5psi of boost. Here's a log of what happened during the pull. fuel press seems to shot up to like 55. Can anyone confirm this? Thanks
Attached Files
File Type: msl 2010-07-17_20.33.44.msl (389.7 KB, 74 views)
skyline397 is offline   Reply With Quote
Old 07-18-2010, 02:32 AM   #2
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Well, your tach signal drops about 300 rpm when it happens along with your injector pulse width but goes back up right away and AFRs return to where they were. It's almost like it thinks your decellerating and the overrun is kicking in. Did it misfire at the same time or do you have any questionable grounds that may be creating a noisy signal?

By the way, how do you know your fuel pressure went up? Hood mounted gauge?
lordrigamus is offline   Reply With Quote
Old 07-18-2010, 03:06 PM   #3
Junior Member
Thread Starter
 
Join Date: Jan 2008
Location: monterey park,ca
Posts: 67
Total Cats: 0
Default

Quote:
Originally Posted by lordrigamus View Post
Well, your tach signal drops about 300 rpm when it happens along with your injector pulse width but goes back up right away and AFRs return to where they were. It's almost like it thinks your decellerating and the overrun is kicking in. Did it misfire at the same time or do you have any questionable grounds that may be creating a noisy signal?

By the way, how do you know your fuel pressure went up? Hood mounted gauge?
i don't think it mis-fires, it just felt like the car jerks back when i reach that psi. As for fuel pressure , i thought it shows on the log, but i guess i am wrong after all. I didn't have this problem when i have the stock injector and the vortech along with ms earlier. These 460 injectors are clean and flowed. I thought putting bigger injectors put less stress on the fuel pump no? Also, what is a sign of fuel pump failure? I notice you had a tre pump, how's that working out for you?
skyline397 is offline   Reply With Quote
Old 07-18-2010, 03:25 PM   #4
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Looks like overboost shut down
Ben is offline   Reply With Quote
Old 07-18-2010, 05:27 PM   #5
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Or this /\.

The pump was holding up good until recently, now it's somewhat questionable. I have had it for a while though. I have a gauge on the fuel line but it's only good when not under load.

I'm not sure it's a fuel issue, it seems like something is deliberately stopping it. Double check your settings.
lordrigamus is offline   Reply With Quote
Old 07-18-2010, 08:01 PM   #6
Junior Member
Thread Starter
 
Join Date: Jan 2008
Location: monterey park,ca
Posts: 67
Total Cats: 0
Default

it seems like the overboost setting, sorry for being such a newb, thank you guys for your help.
skyline397 is offline   Reply With Quote
Old 07-18-2010, 08:24 PM   #7
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Ben is the winner!!!
lordrigamus is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 02:27 AM.